As disclosed in U.S. Pat. No. 7,261,029 to Davis, the Kalashnikov assault rifle, for example the AK-47, and its variants comprise one of the largest groups of firearms on earth. It has been estimated that over 90 million of these firearms have been produced in dozens of countries since their introduction in the Soviet Union in 1946. Developed primarily as a military weapon, the AK-47 became famous for its simplicity of operation and reliability in extreme conditions of use. Because of its mild recoil, the AK-47 has the capability of delivering effective fully-automatic fire at a range of 300 meters. U.S. Pat. No. 7,261,029 to Davis is hereby incorporated by reference.
The AK-74 and variants have issues that make it less than optimal for use as a weapon. These rifles (e.g. the AK-74) lack a means to hold the bolt open after the last round is fired from its magazine. When the last round in a magazine is fired, the shooter does not know that the chamber is empty until the shooter attempts to fire. After the last round in the magazine is fired and ejected, the bolt carrier and bolt loudly slide to breech. Chambering another round requires that a loaded magazine be inserted into the receiver and the bolt carrier be pulled back (cocked). This causes the shooter to lower the rifle from a firing position at the shoulder in order to gain sufficient leverage, making the shooter vulnerable to an aggressor.
It is known to construct detachable firearm magazines such that they will indicate to the shooter when the last cartridge in the magazine has been discharged. The magazines alert the user to the fact that they are empty but do not prevent the forward movement of the bolt carrier and bolt when the magazine is detached from the rifle. Thus, reloading a rifle outfitted with such magazines still requires that the shooter drop the firearm from a firing position to pull the bolt carrier to chamber the first round.
What is needed is an apparatus that will interface with commonly available magazines that are designed to interface with a bolt-hold-open mechanism of existing firearms with firearms that are not provided with a bolt-hold-open mechanism, thereby providing a bolt-hold-open feature after the last round from the magazine is fired.